Paper feed mechanism in typewriters and similar office machines



United States Patent [72] lnventors lngeburg Kuhne .Halberstadt;

Horst Hartung, Erfurt, Germany [21] Appl. No. 659,809 [22] Filed Aug. 10, I967 [45] Patented Dec. 15, 1970 [73] Assignee Veb Optima Buromaschinenwerk Erfurt Erfurt, Germany [54] PAPER FEED MECHANISM IN TYPEWRITERS AND SIMILAR OFFICE MACHINES 4 Claims, 3 Drawing Figs.

[52] U.S.Cl 197/114, 197/ 122 [51] Int. Cl B41j 19/76 [50] Field ofSearch 197/114, 114A,114B,ll5,116,l17,118, 121,122,123

[56] References Cited UNITED STATES PATENTS 1,141,558 6/1915 Kurowski 197/122X 1,345,093 6/1920 Kurowski 197/114 1,532,120 4/1925 Bryant 197/117 Primary ExaminerErnest T. Wright, Jr. Attorney-Nolte and Nolte ABSTRACT: Mechanism comprising a line space ratchet, a paper feed lever having a curved cam surface, a cam follower lever abutting by its own weight on said cam surface and controlling the release of said ratchet, a platen drive wheel, pawl means swingably supported by the paper feed lever, said follower lever being provided with a first limit stop for limiting the movement of the pawl means and with a second limit stop for limiting the movement of the paper feed lever, whereby the paper feed lever has a clamp means cooperative with the second limit stop to prevent lifting of the follower lever. The cam follower lever is attached to a through shaft which also supports a release lever. The release lever is operably connected with a lock lever holding a line space ratchet wheel in position. Upon actuation of the paper feed mechanism and movement of the cam follower lever, the lock lever is swingable out of engagement with the line space ratchet wheel for the purpose of noiseless paper feed.

PATENIED 05m 5 I970 INVENTQRS INGEBURG KUHNE HORST 'HARTUNG ing position.

PAPER FEED MECHANISM IN TYPEWRITERS AND SIMILAR OFFICE MACHINES I This invention relates to a paper .feed mechanism in typewriters and similar office machinesfor feeding the record material such its letter sheets and the like, intoa specific work- Paper feed mechanisms are known from the prior art in which, for the purpose of noiseless paper feeding. the release of the line space ratchet wheel is effected by rolling off a follower lever on a curved surface of the feed lever which is provided with a toothed segment. In some of these devices, the pawls which are necessary for the turningof the typing platen,

are brought into engagement with the platen driving gear by means of 'a limit stop mounted on the feed lever, after likewise being run off on a cam member. Y

Furthermore, mechanisms are known, wherein a" rotatable feed lever having an angular shape is connected by means of a movably arrangedintermediate lever withia toothed segment lever. The latter is pivotally arranged on 'air'ocking lever which is operationally connected with the line space ratchet wheel.

The feed lever, is equalized as to the llcngthiof its travel, is capable of being swung into engagement with the. typing platen pinion, whereby'the rocking lever, the spacinglength of travel of which is limited by means'of two limit stops, is fixedly attached to anaxis, over which, upon actuating the feed lever,

. the line space ratchet wheel is stepwise rotated in a known manner. 4 1

The mechanisms working with a toothed segment and roller lever have the disadvantages that the movement limiting stops for the feed lever and pawl can only unfavorably and with difficulty be installed withinthe frameftha't nosubsequcnt adjustment of the limits is possible, and that additional means are required to hold the rollerlever on the curved-surface.

The mechanisms working with a. toothed segment and movement limiting rocking lever have the disadvantage. that they do not always assure the indispensable reliability of engagemcnt. The movement limiting stops'forthe feed lever and rockirg lever can also only with difficulty be-subsequcntly adjuster.

The object of this invention is to avoid the aforementioned disadvantages.

a reliable, rapid and noiseless-feeding of record material, such as letter sheets and the like, into a' fixed working position.

I I Another object of this invention is to create a mechanism "which, having a minimum space requirement, makes possible In accordance with .the present invention, the paper feed I mechanism line space. ratchet is released by means of a follower levcr rolledoff a'carn surface of the paper feed lever. The follower lever abuts by its own weight againstthe cam surface of the paper feed lever. The follower lever has a first limit stop positioned on it for limiting the movement of the pawl, as well as a second limit stop for limiting the movement of the paper feed lever. Additionally, the paper feed lever is capable of being clamped by means of a clamping lip to prevent the pawl from lifting the follower lever from the-cam surface.

The present invention will now be explained in more detail in an example of one embodiment, with respect to accompanying drawing, wherein: 1

FlG. shows the lateral view of the paper feed mechanism inanunactuated position; y

H6. 2 is a lateral view of the line space ratchet wheel of the paper feed mechanism according to FIG, I; and

FIG. 3 is the paper feed mechanism according to FIG. 1 in an actuated position. I

The paper feed lever l. operationallylshaped as shown in FIG. 1, as well as the driving gear 2 for-the typing platemare pivotally supported on a commonbearing bolt 3 mounted in the right-hand side portion of the carriage. The driving gear 2 engages a pinion 4 which is seated on theplaten shaft 5 and connected by means of two straps (not shown) with the typing platen; A rivet 6, positioned on the paper feed lever. l, pivotally supports a shank spring 8 and the typing platen driving pawl 7 which is capable of being swung into engagement with the driving gear 2. To the right-hand'sidc portion of the carriage, a two-fold angle guide 9, having a curved end surface 90, is fixed in such a manner that the pin 10, which is ri'veted on the pawl 7, abuts, owing to the effect'ofthe shank'spring 8, in a slidingoffposition on the curved end surface 9a; ,1 I

For the purpose of noiseless papcr-feed, a followerlever 1.1, which is attached on a through shaft 12 pivotally supported by both side portions of the carriage, is by means of its-follower 13 in permanent contact with the cam surface la of the paper feed lever l, on'which the follower lever '11 abuts by its own weight. I I

Additionally, the follower lever-J1 is provided with a'limit stop 11a, having the form of a curved projection shaped for limiting the motion of the pawl 7, and with a stop pin 14 to limit themotion of the paper feed lever When the feed lever 1 is lifted away from a restmember A, as shown in H6. 3, a

lever 15 acts with its face 150 on a'bolt' 17 positioned at one end of the lock lever 16. The lock lever 16 ispivotally supported on the lock lever shaft 18 and carries on its lever arm 160 the stop roller 19 for a locking engagement withthe' line space ratchet wheel 20. a v

' The mode of operation of this machine is as follows:

Upon actuation of the paper feed lever l, the pawl 7 initially resting on the curved end surface 9a of the angle guide 9 is moved upwardly and engages, owing to the resilience of the shank spring 8, the driving gear 2, which transmits its movement over the pinion 4 to the typing platen. in known manner the inserted sheet of paper can be seized by the movement of the typing platen and can quickly be brought into a specific operating position.

At the same time, the follower l3, following the rotating cam surface In of the paper feed lever l, is raised consequently, the followerlever' ll is angularly displaced and turns the shaft 12 until the releaseslever l5 lifts the lock lever 16 and as a result the stop roller 19 swings out of engagement with the line space ratchet wheel 20. The driving gear 2 which is driven by the pawl 7, during the entir'etravel of the paper feed lever 1, thus secures the intended rotary movement of the typing platen. When the predetermined. depth of insertion of the paper sheet is attained, the'pawl 7 strikes with its face 7a against the adjustable limit stop Ila of the. follower lever 11, and immediately after the travel of the paper feed lever l is stopped due to the engagementof it's'hook-shaped clamping lip lb with the stop pin (The-clamping of theclamping lip 11; is provided to prevent further lifting ofthe follower lever driving gear 2, until the former, owing to the running-up of the in conventional carriages and it insures a'noiseless feeding of riveted pin 10 on the'curved end surface 9a, is completely out of engagement with the driving gear 2. Similarly, the roller lever '11 falls back again into its starting position and the stop roller 19 is again'swung into engagement with the line space ratchet wheel 20.

The mechanism according to this'invcntlon. can be installed record material as well as operational reliability of the entire system. Weclaim:-

l. in a typewriter and similar office .machines, carriage with driv ng gear, aid paper feed leverprovided with cam the form of a protruding pin forcooperation with said clamp means.

3. The paper feed mechanism according to claim I, wherein said pawl means are pivotably supported on a rivet mounted on said paper feed lever, and biased by means of a shank spring.

4. The paper feed mechanism according to claim 3 further comprising an angle guide 'having a curved end surface for guiding said pawl means out of engagement with said driving gear and a tension spring for biasing said paper feed lever. 

